Re: kern/53202: Kernel hangs running t_ptrace_wait:resume1 test

[Andreas Gustafsson <gson%gson.org@localhost>]

The following reply was made to PR kern/53202; it has been noted by GNATS.

From: Andreas Gustafsson <gson%gson.org@localhost>
To: christos%NetBSD.org@localhost
Cc: gnats-bugs%NetBSD.org@localhost
Subject: Re: kern/53202: Kernel hangs running t_ptrace_wait:resume1 test
Date: Fri, 27 Apr 2018 15:55:19 +0300

 Taylor R Campbell wrote:
 >  It may be more prudent to find why the change to cv_wait_sig worked
 >  around whatever the root cause of the problem with Go was, but I don't
 >  have any brilliant ideas about that.
 >  
 >  In particular, it smells like there is a missing wakeup in the lwp
 >  exit logic, perhaps owing to an obscure case of a signal delivery that
 >  happens to cause cv_wait_sig to return early.  But exactly where the
 >  wakeup needs to happen is unclear.  The condition that the relevant
 >  cv_wait is waiting for in the `exiting' case of lwp_wait is not
 >  obvious -- there's a whole string of things whose change might trigger
 >  it.
 
 Christos - is there a PR for the problem with Go that was the
 motivation for kern_lwp.c 1.191?
 -- 
 Andreas Gustafsson, gson%gson.org@localhost